Adjustable vacuum breaker fill valve

ABSTRACT

A fill valve for controlling liquid level in a toilet water tank or other tank includes a valve head assembly positioned at a selected level in the tank by a telescoping riser assembly with liquid inlet and outlet conduits extending toward the tank bottom. An adjusting nut on a stationary riser engages thread structures on inlet and outlet conduits for raising or lowering the valve head assembly and adjusting the liquid level. A main valve in the head assembly is controlled by a non-horizontal diaphragm separating a vent chamber and a control chamber. The control chamber is pressurized as liquid rises to the selected level by a standpipe extending downwardly in the tank. The valve closing and opening levels are offset by partly filling the vent chamber with liquid when the main valve is open to hydraulically load the diaphragm. A vacuum breaker valve obstructs backflow through the valve, vents the flow path when the valve is closed, and regulates flow into the vent chamber when the valve is open.

The present invention relates to a fill valve for water level control intoilet tanks and similar tanks.

Fill valves function to maintain a predetermined liquid level in a tankor reservoir, and are used widely in toilet tanks and other tanks. Atypical fill valve includes an inlet adapted to be connected to a supplyof pressurized liquid, an outlet communicating with the tank, a valvefor controlling flow into the tank, a device for detecting the level ofliquid in the tank and structure for opening the valve when the detectedliquid level is below the predetermined level. In the past, many fillvalves have been of the ball cock variety wherein the valve iscontrolled by a float. My U.S. Pat. Nos. 3,895,645 and 4,180,096disclose fill valves having advantages over ball cocks, includingcompactness and cost. Those fill valves are entirely submerged and usediaphragms responsive to liquid pressure to detect liquid level.

While the devices disclosed in my prior patents have been successful inachieving their intended purposes, it may be desirable in some instancesthat the fill valve not be entirely submerged to the end that anatmospheric vacuum breaker can be included in the liquid flow path.Accordingly, one object of the present invention is to provide animproved fill valve of the type in which the valve or a portion thereofis mounted in a tank above the liquid level and wherein vacuum breakercapability is provided.

One difficulty which has been encountered with ball cocks and other fillvalves extending above the water level results from the wide variety oftank configurations in which such valves may be used. Variations in tankheight make it desirable that the height of the fill valve, as well asthe water level, be adjustable so that the fill valve has universalapplication in different tanks. Another object of the present inventionis to provide a fill valve which is reliably and easily adjustable toaccommodate tanks of various depths.

The fill valves disclosed in my patents referred to above make use of ahighly reliable and efficient valve system including a main valve and apilot valve controlled by a diaphragm serving to detect water level inthe tank. It is desirable to incorporate this valve system in a nonsubmerged fill valve. Accordingly, it is yet another object of theinvention to provide a fill valve including an improved structureincluding a downwardly extending standpipe for controlling a pressureresponsive diaphragm in accordance with liquid level in a tank.

It is desirable in the operation of a fill valve that the opening andclosing of the valve be effected positively in order to avoid anytendency to "hunt" or operate in a partly open condition. A furtherobject of the present invention is to provide a fill valve whereinstable operation is achieved because the opening and closing waterlevels are offset from one another.

Among the other important objects of the present invention are toprovide a fill valve overcoming disadvantages of fill valves used in thepast; to provide a fill valve which is safe and easy to use, is quiet inoperation, and which is simple and reliable.

In brief, the objects and advantages of the present invention includingthose referred to above are achieved through the provision of a fillvalve including a valve head assembly positioned at a selected elevationin the tank above the predetermined water level by a telescoping riserassembly. The riser assembly includes a riser having a shank portionfixed to a wall of the tank and including inlet and outlet sections.Inlet and outlet flow conduits extend downwardly from the valve headassembly and are telescopically adjustable with respect to the inlet andoutlet sections of the riser. An adjusting nut associated with the riserthreadedly engages the inlet and outlet conduits for adjustment of theheight of the valve assembly in the tank and simultaneous adjustment ofthe predetermined liquid level.

A main valve in the valve head assembly opens and closes communicationbetween the inlet and outlet conduits under the control of a diaphragmseparating a vent chamber and a control chamber. A vacuum breakerchamber is disposed in an outlet flow path extending from the main valveto the tank interior. The vacuum breaker chamber includes first portmeans communicating with the main valve, second port means communicatingwith the vent chamber and third port means communicating downstreamalong the outlet flow path. A vacuum breaker valve in the form of asimple, washer-like, elastomeric member overlies the first port meanswhen the main valve is closed and the second port means when the mainvalve is open.

A standpipe communicating with the control chamber extends downwardly inthe tank and applies pressure to the diaphragm in response to increasingliquid level. The diaphragm is non-horizontal, and when the main valveis open, the vent chamber is partly filled with liquid in order tohydraulically load the diaphragm with the result that the liquid levelrequired to close the main valve is increased. The vent chamber isdrained when the main valve is closed so that a lower liquid levelresults in reopening of the main valve.

The above and other objects and advantages of the invention may be bestunderstood from the following detailed description of the embodiment ofthe present invention illustrated in the drawings, wherein:

FIG. 1 is a side elevational view, with portions broken away, of a fillvalve constructed in accordance with the invention;

FIG. 2 is another side elevational view of the fill valve, taken fromthe line 2--2 of FIG. 1;

FIG. 3 is a sectional view on an enlarged scale taken along the line3--3 of FIG. 2 and illustrating portions of the riser assembly of thefill valve;

FIG. 4 is a sectional view of the head assembly and part of the riserassembly of the fill valve, taken along the line 4--4 of FIG. 2;

FIG. 5 is a sectional view taken along the line 5--5 of FIG. 4;

FIG. 6 is a sectional view taken along the line 6--6 of FIG. 4;

FIG. 7 is a sectional view taken along the line 7--7 of FIG. 4;

FIG. 8 is a sectional view taken along the line 8--8 of FIG. 4;

FIG. 9 is a sectional view taken along the line 9--9 of FIG. 4;

FIG. 10 is a fragmentary sectional view taken along the line 10--10 ofFIG. 5;

FIG. 11 is an exploded perspective view, partly in section, of thediffuser, main valve member and cap prior to assembly;

FIG. 12 is an exploded perspective view, partly in section, of the body,diffuser, seal, vacuum breaker valve member and cap prior to assembly;and

FIG. 13 is an exploded perspective view, partly in section, showing thebody of the fill valve with other components assembled therewith and ofthe diaphragm assembly and cover prior to assembly.

Having reference now to the drawings, there is illustrated a fill valveconstructed in accordance with the principles of the present inventionand designated as a whole by the reference numeral 20. Fill valve 20 ismounted to a wall 22 of a tank such as a toilet water tank, andfunctions to maintain the level of liquid within the tank at apreselected level. Although the fill valve 20 is intended to be mountedas illustrated in an aperture 24 in the bottom wall 22 of the tank,principles of the invention are applicable also to tanks having othertypes of inlet arrangements such as a sidewall inlet.

In general, the fill valve 20 includes a riser assembly generallydesignated as 26 (FIGS. 1-4) by means of which a valve head assemblygenerally designated as 28 can be raised or lowered to accommodate tanksof different heights. The valve head assembly includes a main or controlvalve assembly generally designated as 30 (FIG. 4) controlled by a waterlevel responsive pressure detecting system generally designated as 32(FIG. 4) for admitting water to the tank when the water level fallsbelow a selected level. A vacuum breaker valve assembly generallydesignated as 34 (FIG. 4) resists backflow through the fill valve 20,provides an atmospheric vacuum breaker, and contributes as describedbelow to operation of the fill valve 20 in a positive on and off manner.

The main components of the fill valve 20 are preferably formed of moldedplastic material and are readily assembled together without separatefasteners or the like to define the various operating sections of thehead assembly 28. These main components include a body 100 adjustablyrelated to a riser 200, and a cover 300, cap 400 and diffuser 500assembled with the upper portion of body 100 to form the head assembly28. To assist in interrelating the accompanying drawings with thiswritten description, elements of the valve components 100, 200, 300, 400and 500 respectively are designated by three digit reference numeralsbeginning with the same digit 1, 2, 3, 4 or 5.

Riser 200 (FIGS. 1-4) includes a shank portion 202 extending through thetank wall aperture 24. The shank is threaded to receive a mounting nut35 for supporting the riser 200 and a coupling nut 36 cooperating with athrust washer 37 and seal 38 to connect the riser shank 202 to a conduit39 supplying water or other liquid under pressure to the fill valve 20.A gasket 40 held in compression by a lower flange 204 of riser 200 sealsthe aperture 24 in the tank wall 22.

Within the tank, the riser 200 includes a generally circular cylindricalinlet section 206 and outlet section 208 extending generally parallelwith one another. The inlet section communicates with supply conduit 39by way of shank 202, and the outlet section 208 communicates with theinterior of the tank by way of an outlet port 210 adjacent the baseflange 204 at the lowermost portion of the outlet section 208.

Inlet and outlet sections 206 and 208 are elongated tubular structuresextending parallel to one another upwardly from the tank bottom. Theyare joined together at the bottom by a web portion 212 and at the top byan upper flange 214. Upper flange 214 merges with a generally U-shapedwall 216 to define a generally rectangular opening or window 218 at thetop of the outlet section 208. The opening 218 is accessible from bothsides of the riser 200 and also is open to the upper portion of theinlet section 206 (see FIGS. 1 and 4).

The body 100 includes an upper head portion 102 generally of anopen-topped, cup shape (FIG. 12). Descending from head portion 102 arean inlet conduit 104 and an outlet conduit 106 which, along with riser200, constitute the riser assembly 26. Conduits 104 and 106 extendparallel to one another and are stiffened with respect to one anotherand with respect to head portion 102 by a number of webs 108. In theillustrated embodiment of the invention, the inlet and outlet conduits104 and 106 are intended to be vertical, and the head portion 102 isinclined at an angle of 45°. The non-horizontal orientation of the headassembly 28 and of the head portion 102 provides an important functionin the operation of the fill valve 20 as discussed in more detail below.

Inlet and outlet conduits 104 and 106 are telescoped within the inletand outlet sections 206 and 208 of the riser. An O-ring 41 seals theexterior of the inlet conduit 104 against the interior of the inletsection 206. A strainer 42 and flow restrictor 43 are mounted at the endof the inlet conduit 104. When the main valve assembly 30 of the fillvalve 20 is open, liquid flows from the supply conduit 39 into the inletsection 206 and then into the inlet conduit 104 toward the head assembly28. From the head assembly 28, liquid flows through the outlet conduit106 into the outlet section 208 and into the tank through the outletport 210.

Fill valve 20 may be installed in tanks of various heights, and inaccordance with the invention the height of the fill valve is readilyadjustable. Riser assembly 26 includes not only the riser 200 and partsof body 100, but also an adjustment nut 44 located within the opening218 of the riser 200. Both the inlet conduit 104 and the outlet conduit106 include thread structure in the form of teeth 110 extending asubstantial distance along a their length. The teeth 110 form rack gearstructures threadedly engaged by an external thread 44A and an internalthread 44B of the adjustment nut 44, the threads 44A and 44B eachincluding slightly less than 1 complete convolution.

The body 100 is illustrated in FIGS. 1, 2 and 4 in substantially itslowermost position with respect to riser 200. In order to adjust theheight of the fill valve 20, nut 44 is grasped at the open sides ofopening 218 and rotated. Engagement of threads 44A and 44B with teeth110 causes the body 100 to be raised or lowered with respect to theriser 200 to the desired height. Due to the mechanical advantage of thethreads and teeth and to the friction provided by O-ring 41, the body100 will remain in any position to which it is adjusted.

The height of the body 100 may be adjusted while the fill valve 20 issubjected to liquid pressure. If the body 100 is raised to an extremeupper position, the O-ring 41 moves past a pressure relief port 213 andinlet liquid is bypassed directly to the interior of the tank. Thisprevents inlet pressure from forcefully ejecting the body 100 from theriser 200 in the event that the body 100 is raised too far.

Adjustment of the relative positions of body 100 and riser 200 variesthe overall height of the fill valve 20 and determines the elevation ofthe head assembly 28 above the tank wall 22. The water level maintainedby the fill valve 20 within the tank is determined with respect to theposition of the head assembly 28, so that adjustment of the height ofthe head assembly 28 also adjusts the water level.

In addition to the head portion 102 of body 100, the head assembly 28 ofthe fill valve 20 includes the cover 300, the cap 400 and the diffuser500. As seen in FIG. 4, when the fill valve 20 is assembled, thediffuser 500 is captured within the cup shaped head portion 102 of thebody 100 by the cap 400. The main valve assembly 30 and the vacuumbreaker valve assembly 34 are located beneath the cap 400 and above thediffuser 500. The cover 300 is attached over the open top of the bodyhead portion 102 and cooperates with the body head portion 102 and cap400 to provide a diaphragm cavity 52 of the pressure detecting system32.

Diffuser 500 nests within the head portion 102 and provides a path forthe flow of liquid from the main valve assembly 30 to the vacuum breakervalve assembly 34. An annular top wall 502 defines the bottom of avacuum breaker chamber 45. A central hub-like element 504 extends abovetop wall 502 and defines the peripheral, outermost portion of a valvingsurface 46 of the main valve assembly 30. Body 100 includes a circularvalve seat 114 in head portion 102 defined by the upward end of inletconduit 104. Seat 114 is surrounded by a plurality of radially outwardlydirected walls 116 defining therebetween a number of main valve ports47. Seat 114 and walls 116 are received within the central hub 504 ofthe diffuser 500, and the ports 47 are disposed in the valving surface46 and have increasing widths in the radially outward direction.

Liquid flowing from the main valve assembly 30 through the main valveports 47 reaches a radially inward region 506 of the diffuser 500disposed below the top wall 502 (FIGS. 4 and 9). The diffuser includes acontinuous outer skirt or wall 508, and the annular region between theinward portion 506 and the outer wall 508 is generally divided intoquadrants by four different wall structures 510, 512, 514 and 516. Aswill appear in more detail, wall structure 510 accommodates an outletport 48 from the vacuum breaker valve assembly 34. Wall structures 512define a pair of diffuser outlet flow ports. Wall structure 514 is adividing wall between two quadrants of the diffuser flow path.

In order to dissipate flow velocity and attenuate liquid pressures inthe fill valve 20, the diffuser includes a plurality of baffle walls 516in each of the four flow path quadrants. The baffle walls 516 arealternately interleafed in opposite directions to define flow pathsegments having numerous substantially right angle turns, each of whichresults in loss of energy in flowing liquid. The effect of the repeatedright angle turns is to regulate the flow velocity through the fillvalve 20 to a desired value while dissipating inlet pressure. Otherabrupt changes of direction of liquid flowing through the fill valve 20,for example at the valving surface 46, the diffuser outlet ports 512,and the outlet port 48 have a similar effect. The flow restrictor 43 isincluded to help regulate the overall flow characteristics of the fillvalve 20.

In order to position and support the diffuser 500, the head portion 102of body 100 includes a base wall 118 having an upwardly directed arrayof recesses 120 (FIGS. 4, 7, 8, 10 and 12). When the diffuser 500 isnested in the body 100, the outer wall 508, the wall structures 510, 512and 514 and the baffle walls 516 are received in body recesses 120 sothat the portions of the diffuser are well supported and so that liquidflow is not bypassed beneath the diffuser. Body head portion 102includes a circular side wall 122 extending upwardly from base wall 118within which the diffuser outer wall 508 is snuggly and slideablyreceived.

Cap 400 holds the diffuser 500 in place in the body 100 and is attachedto the body 100 with a bayonnet lock structure. A seal 56 is capturedbetween the body 100 and cap 400. The cap includes an annular outer wall402 from which a number of bayonnet projections 404 radially extend. Thebody 100 includes a similar number of bayonnet latch ledges 124. Tomount the cap in the body, the cap is inserted within the circularsidewall 122 with the projections 404 displaced from the ledges 124. Thecap is then rotated to the interlocked position shown in the drawings(see FIG. 6) with cam surfaces on the projections 404 facilitating thisaction and with stop surfaces on projections 404 engaging the ends ofledges 124 in the fully assembled position.

As appears in FIGS. 4 and 7, the cap 400 holds the diffuser 500 firmlyin place in body 100. Annular wall 402 includes a portion engaging acircular upstanding wall 518 on the diffuser (see also FIG. 12). Inaddition, cap 400 includes a central, hub-like portion 406 engaging theouter periphery of the central hub 504 of the diffuser 500.

The underside of cap 400 cooperates with diffuser 500 in defining thevacuum breaker chamber 45. In addition, the central hub 406 of the capdefines a chamber 49 above the valving surface 46 for the main valveassembly 30. When the cap 400 and diffuser 500 are assembled with body100, a vacuum breaker valve member 50 is captured in the vacuum breakerchamber 45 and a main valve member 51 is captured in the main valvechamber 49.

Vacuum breaker valve member 50 preferably is a simple washer-like bodyof rubber or other elastomeric material captured freely and looselywithin the vacuum breaker chamber 45. Valve member 50 cooperates withthe diffuser outlet ports 512 to obstruct possible back flow through thefill valve 20 and also cooperates with a circular array of vent ports408 in the cap 400 to vent the vacuum breaker chamber 45 to atmospherewhen the fill valve 20 is closed.

The main valve member 51 is firmly captured at its periphery between thehub portions 406 and 504 of the cap 400 and diffuser 500. The centralportion of the main valve member 51 includes an opening slideablymovable about a projection 410 extending downwardly from the cap hubportion 406. Projection 410 includes notches 412 (FIG. 11) providing arestricted flow path from the inlet conduit 104 to main valve chamber49.

Cover 300 is also attached to the body head portion 102 by a bayonnetlatch arrangement. The cover includes a top wall 302 with a dependingskirt wall 304 fitting around the circular side wall 122 of the body100. The bayonnet latch projections 126 extend radially outwardly fromthe sidewall 122 of the body 100 and engage latch ledges 306 extendingradially inward from the skirt wall 304 of the cover. To mount the cover300 on the body 100, the cover is placed over the body head portion 102with the projections 126 spaced from the ledges 306. The cover isrotated to effect the bayonnet latch. Cam surfaces on the latchprojections 126 assist in effecting the latch and stop surfaces definethe fully assembled position.

Pressure detecting system 32 includes a diaphragm cavity 52 definedabove the cap 400 and within the cover 300. This chamber is subdividedinto a lower vent chamber 52A and an upper control chamber 52B by meansof a diaphragm 53 held between the cover 300 and body 100. The diaphragm53 includes a beaded periphery sealingly clamped between the cover andbody. The diaphragm 53 is formed of a suitable flexible and resilientmaterial such as rubber, and a stiffening disc 54 is molded togetherwith the diaphragm 53 as by filling an array of small holes in the disc54 with the material of the diaphragm 53 as illustrated (FIGS. 4 and13).

A projection 308 extends downwardly from a cover top wall 302 and limitsupward movement of the diaphragm 53 in order to prevent undesirablestress on the diaphragm. A pilot valve portion 53A of the diaphragmcooperates with a pilot valve seat 414 of cap 400 extending from thevent chamber 52A to the main valve chamber 49 by means of a smallpassage extending through the central hub portion 406 of the cap 400.

The lower vent chamber 52A of the diaphragm cavity 52 is freely ventedto the interior of the tank above water level by means of vent ports 128formed in the circular sidewall 122 of body 100. Clearance between theskirt wall 304 of the cover and the sidewall 122 of the body assuresunrestricted venting of the chamber 52A.

The upper control chamber 52B of the diaphragm cavity 52 communicates bymeans of a passage 310 with the interior of a downwardly extendingstandpipe portion 312 of the cover 300. When liquid level rises abovethe bottom end 314 of the standpipe, air trapped within the controlchamber 52B increases in pressure and applies a force to the diaphragm53 tending to close the pilot valve portion 53A against the pilot valveseat 414.

Operation of the fill valve 20 will now be described. The fill valve isinstalled in a liquid containing tank with the supply conduit 39interconnected with a source of pressurized liquid. The elevation of thehead assembly 28 is adjusted by operation of the adjustment nut 44 asdescribed above to accommodate the height of and to select the liquidlevel to be maintained in the tank. The interior of the inlet conduit104 below the main valve member 51 is continuously and directlycommunicated with pressurized liquid. The fill valve 20 functions tomaintain a predetermined water level, and to refill the tank when thewater level falls.

When water level within the tank is at the predetermined level, the mainvalve member 51 is closed against the main valve seat 114 and liquid isprevented from flowing through the main valve ports 47. Restrictedcommunication along the notches 412 in projection 410 pressurize themain valve chamber 49 because trapped and pressurized air within thecontrol chamber 52B operates diaphragm 53 to close the pilot valve seat414. The main valve member 51 is positively clamped shut because thepressurized upper area within the main valve chamber 49 is larger thanthe pressurized lower area circumscribed by the main valve seat 114.

When water level within the tank falls sufficiently, the pressure withinthe control chamber 52B falls and the pilot valve portion 53A of thediaphragm 53 moves away from the pilot valve seat 414. This reduces thepressure above the main valve member 51 in the main valve chamber 49 andthe main valve member 51 opens with a radial peeling or rolling actionaway from the valve seat 114 and the valving surface 46. As a result,liquid flows from the inlet conduit 104 through the valve ports 47 tothe central inward region 506 of the diffuser.

Within the diffuser, liquid flows through the four quadrants of thediffuser flow path among the baffle walls 516. Liquid reaching the outerperiphery of the diffuser 500 merges at the two diffuser outlet ports512 from which it flows upwardly into the vacuum breaker chamber 45beneath the vacuum breaker valve member 50. Normally the valve member 50lies loosely in the chamber approximately in the position illustrated inFIG. 4 so that the flow path through the head assembly 28 between theinlet and outlet conduits 104 and 106 is vented to atmosphere in thevacuum breaker chamber 45 by way of the cap vent ports 408 and body ventports 128. When liquid flows through the fill valve 20, the force ofliquid exiting from the diffuser outlet ports 512 drives the vacuumbreaker valve member 50 upwardly toward the cap vent ports 408permitting unrestricted flow through the vacuum breaker chamber 45. Thisflow reaches the outlet conduit 106 through the vacuum breaker outletport 48. Port 48 is defined by the upwardmost end of the outlet conduit106, and this end includes a portion projecting slightly into the vacuumbreaker chamber to hold part of the vacuum breaker valve member 50slightly above the top wall 502 of the diffuser 500.

The flow leaving the vacuum breaker chamber 45 through the port 48reaches the fill valve outlet port 210 by way of the outlet conduit 106and the outlet section 208 of the riser 200. A part of this flow isdiverted through a refill passage 130 (FIG. 8) extending from the outletconduit 106. When fill valve 20 is used with a toilet water tank, therefill passage 130 communicates by means of a refill tube 55 with thetoilet tank overflow pipe for refilling the toilet bowl and trap aftereach flushing operation.

In accordance with an important feature of the present invention, theopening and closing operations of the fill valve 20 are offset from oneanother relative to liquid level in the tank. This provides a latchingor detenting operation preventing unstable opening and closing operationof the valve. This offset in operation is accomplished in a veryreliable and simple, automatic manner by hydraulic loading of thediaphragm 53 when the main valve assembly 30 is open to refill the tank.

When liquid is flowing through the fill valve 20 in a tank fillingoperation, part of the flow is diverted to the lower, vent chamber 52Aof the diaphragm cavity 52. One component of this diverted liquid flowsthrough the notches 412 in the cap projection 410 and through the pilotvalve seat 414 into the chamber 52A. To permit another component ofdiverted flow, the cap 400 includes downwardly extending projections 416adjacent the vent ports 408 (FIGS. 4 and 11). The projections 416prevent the vacuum breaker valve member 50 from closing entirely overthe vent ports 408 so that a part of the liquid flowing through thevacuum breaker chamber 45 flows past the valve member 50 and into thediaphragm vent chamber 52A. Since the valve member 50 is formed of aflexible material, this flow component is automatically compensated andtends to remain constant despite variations in liquid inlet pressure. Aspressure increases, the valve member 50 is forced more firmly over thevent ports 408. Conversely, if pressure is less, the valve member 50automatically decreases the restriction to flow through the ports 408.

Diaphragm 53 is non-horizontal and the level of liquid within thechamber 52A during refill of the tank is controlled to provide apredetermined liquid pressure against the underside of the diaphragm.Moreover, after refilling of the tank, chamber 52A is emptied of liquidsufficiently so that liquid pressure against the diaphragm 53 isdiscontinued.

More specifically, liquid flows from the chamber 52A in two differentways. When the liquid flowing through the ports 408 and the pilot valveseat 414 reaches the level of the vent ports 128 in the body sidewall122, the liquid overflows in a relatively unrestricted fashion out ofthe chamber 52A. Consequently, the elevation of the body vent ports 128establishes an approximate predetermined maximum liquid level within thechamber 52A.

Liquid overflowing from the diaphragm vent chamber 52A through the ports128 is returned quietly to the interior of the tank without undesirablesplashing noise. This liquid descends to ledges 132 extending radiallyoutwardly from the sidewall 122 of the body head portion 102. Liquidreaching this ledge flows downwardly along the ledge between the bodysidewall 122 and the cover skirt wall 304 to a region above thestandpipe 312 (see FIG. 6). At this region, the ledge 132 is not presentand the liquid descends to a surface 316 defined in part by thestandpipe 314 and in part by a projecting ledge 318. The surface 316guides the overflowing liquid smoothly toward the inlet section 206 ofthe riser 200 along which the liquid flows in a nonturbulent fashiontoward the bottom of the tank.

Liquid maintained at a predetermined level in chamber 52A by overflowthrough vent ports 128 immerses a predetermined part of the area of thebottom of diaphragm 53. This applies a predetermined force against thediaphragm tending to hold the diaphragm away from the pilot valve seat414. As liquid level in the tank increases, pressurized air trappedwithin the control chamber 52B tends to move the diaphragm against thepilot valve seat 414. Liquid pressure in chamber 52A prevents the pilotvalve seat 414 from being closed until the liquid reaches a levelsignificantly higher than the level which would result in valve closureif liquid were not present in chamber 52A to hydraulically load thediaphragm 53.

When the pilot valve seat 414 is closed by the pilot valve portion 53Aof the diaphragm, pressure increases within the main valve chamber 49and firmly clamps the main valve member 51 closed over the valve seat114 and against the annular array of main valve ports 47, thusterminating flow through the fill valve 20. After the valve is closed,liquid is permitted to flow from the vent chamber 52A to discontinuehydraulic loading of the diaphragm 53. As a result, the liquid levelwhich results in opening of the pilot valve seat 414 is offset from andis lower than the liquid level which results in closing of the valve.

In order to empty the chamber 52A after a refilling operation of thefill valve 20, a restricted flow path from the chamber 52A is provided.Liquid in the chamber can flow in a restricted fashion through a pair ofsmall openings 134 provided in the lowermost region of chamber 52A (seeFIGS. 10 and 13). Additional liquid may flow through clearances providedbetween the bayonnet latch projections 404 of the cap 400 and thebayonnet latch ledges 124 of the body 100. As a result of the restrictedflow, liquid within the chamber 52A descends below the diaphragm 53 ashort time after the valve is closed. In order effectively to achievehydraulic loading of the diaphragm, the diverted flow into the chamber52A should be greater than the restricted flow from chamber 52A andshould be sufficient to cause a controlled overflow through the ventports 128.

While the invention has been described with reference to details of theillustrated embodiment, it should be understood that such details arenot intended to limit the scope of the invention as defined in thefollowing claims.

What is claimed and desired to be secured by Letters Patent of the United States is:
 1. A liquid level control valve for use with a liquid tank comprising in combination:an inlet conduit; a valve seat communicating with said inlet conduit; a main valve member movable to open and close said valve seat; means for controlling said valve member in response to the level of liquid in the tank; said controlling means including a cavity and a diaphragm dividing said cavity into a vent chamber and a control chamber means for pressurizing said control chamber in accordance with the level of liquid in the tank; an outlet flow path extending from said valve seat to the interior of said tank and including a vacuum breaker chamber; first port means in said vacuum breaker chamber communicating with said valve seat; second port means in said vacuum breaker chamber communicating with said vent chamber; third port means in said vacuum breaker chamber communicating downstream along said outlet flow path; a vacuum breaker valve in said vacuum breaker chamber overlying said first port means when said main valve member is in said closed position and overlying said second port means when said main valve member is in said open position; and a restricted flow path between said vacuum breaker chamber and said vent chamber for admitting liquid to said vent chamber when said main valve member is open to delay closing of said main valve member.
 2. A liquid level control valve as claimed in claim 1 wherein said vacuum breaker chamber is generally annular with interfacing annular top and bottom walls, said first and second port means being located respectively in said bottom and top walls, and said vacuum breaker valve being an elastomeric washer-like body of generally uniform cross-section around its central axis.
 3. A liquid level control valve as claimed in claim 1 wherein said diaphragm is nonhorizontal; and means including said restricted flow path for partly filling said vent chamber with liquid when said main valve member is in its open position.
 4. A liquid level control valve as claimed in claim 3, said partly filling means including obstruction means in said vacuum breaker chamber for preventing said vacuum breaker valve from entirely closing said second port means.
 5. A liquid level control valve as claimed in claim 4, said partly filling means further including first relatively unrestricted drain means spaced from the bottom of said vent chamber and second restricted drain means at the bottom of said vent chamber.
 6. A liquid level control valve as claimed in claim 1, said pressurizing means including a stand pipe extending downwardly from said control chamber within said tank.
 7. A valve for controlling the level of liquid in a tank or the like comprising:an inlet and an outlet and a valve means for opening and closing communication between the inlet and the outlet; value control means including a cavity; a diaphragm mounted in said cavity dividing said cavity into a vent chamber and a control chamber; said diaphragm being mounted in said cavity in a nonhorizontal position; means for applying pressure in said control chamber in accordance with liquid level in the tank; valve operating means for opening and closing said valve means in response respectively to expansion and contraction of said control chamber; and means for delaying expansion of said control chamber during filling of said tank; said delaying means including means for partly filling said vent chamber with liquid when said valve means is open.
 8. The valve of claim 7, said vent chamber including a restricted drain at the bottom of the vent chamber and a relatively unrestricted drain spaced from the bottom of the vent chamber; said partly filling means including a flow path extending from said valve means to said vent chamber; and restriction means in said flow path for admitting liquid into said vent chamber at a flow rate greater than the flow rate of said restricted drain.
 9. The valve of claim 8 wherein said restriction means includes flow regulation means for decreasing the flow restriction in response to decreasing inlet liquid pressure.
 10. The valve of claim 7, said pressure applying means including stand pipe means communicating with said control chamber and extending downwardly in said tank.
 11. A method for controlling a tank filling valve comprising the steps of:applying increasing pressure to a control chamber at a first side of a diaphragm as liquid level rises in the tank; venting a vent chamber to atmosphere at the second side of the diaphragm; closing the valve when the diaphragm moves away from the control chamber; opening the valve when the diaphragm moves toward the control chamber; and delaying closing of the valve by applying a temporary loading pressure higher than atmospheric pressure against the second side of the diaphragm when the valve is open.
 12. The method of claim 11 performed with a nonhorizontal diaphragm wherein said temporary loading pressure applying step includes the step of admitting liquid to the vent chamber at the second side of the diaphragm.
 13. The method of claim 12 wherein said temporary loading pressure applying step includes the further steps of:maintaining liquid level in the vent chamber at a predetermined level when the valve is open; and emptying liquid from the vent chamber when the valve is closed. 